The present invention relates to 5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine-2(3H)-thione compounds and to a method of use of these compounds for the preparation of 2,2'-dithiobis(5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine) and 2-chlorosulfonyl-5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine compounds. It further relates to the 2,2'-dithiobis(5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine) compounds prepared and the use of these compounds for the preparation of 2-chlorosulfonyl-5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine compounds.
5-Alkoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds that are potent herbicides are described in U.S. Pat. No. 5,163,995. They are disclosed to be prepared in a multistep process that involves the preparation of 2-chlorosulfonyl-5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine intermediate compounds by the chloroxidation of the corresponding 2-(benzylthio or C.sub.2 -C.sub.4 alkylthio)-5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine compounds with chlorine in an aqueous medium and the subsequent condensation of these intermediate compounds with substituted aniline or N-trialkysilylaniline compounds. The yields of the desired herbicidal products are variable, often due to the low yields obtained in the chloroxidation and the impure nature of the 2-chlorosulfonyl-5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine intermediate compounds obtained. The process, further, creates an excessive amount of waste.
Improved methods of preparing the 2-chlorosulfonyl-5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine intermediates for 5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide compounds, for example, methods that give higher yields or higher purities or involve simplified operations, are of great interest.
5-Alkoxy[1,2,4]triazolo[1,5-c]pyrimidine-2(3H)-thione and 2,2'-dithiobis(5-alkoxy[1,2,4]triazolo[1,5-c]pyrimidine) compounds have not been described in the art.